Double-centered joint for rules



L. HEDGE.

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No. 185. w Patented April 29, 1837.

I z vyz. FY 7 a I I LEMUEL HEDGE, OF HARTFORD, CONNECTICUT.

DOUBLE-CENTERED JOINT FOR RULES.

Specification of Letters Patent No. 185, dated April 29, 1837.

To all whom it may concern Be it known that I, LEMUEL HEDGE, of Hartford in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in the Manufacture of Rules, called Carpenters Rules, Box- Rules, 810.; and I do hereby declare that the following is a full and exact description.

The nature of my invention consists in applying double centered joints to jointed rules, in the room and stead of the single centered joints heretofore used.

To enable others skilled in the art of making rules to make and use my invention, I will proceed to describe the construction and operation of a double centered joint of the best form which has suggested itself to my mind, deeming it unnecessary here to describe the many shapes in which it may be applied without affecting the governing principle, which is that of its turning on two centers instead of one, or its permitting each leg of the rule to turn on its own peculiar center an equal portion of the half of a revolution which is required to close or fold an opened rule together.

I provide two thin plates of metal, or other substance, of the form shown at Figure 1 (see accompanying drawing.) I then shape one end of each piece intended for the legs of the rule, as shown at Fig. 2. The ends thus shaped, are then to be indented on each side to receive the plates as shown at Fig. 3. The plates are now to be placed in their indentations, and pins which also serve as pivots on which the legs of the rule are to turn are passed through the holes pre pared to receive them, and shown at a, a, a, a, Figs. 1 and 3. These pins being riveted fast in the countersunk holes of the plates complete the connection of the two legs of the rule, and form the oint. The angular projections of the plates 5 b Fig. 1, are useful in permitting the turning of each leg of the rule on its center no more than is sutficient to insure the opening of the rule to a straight line, and closing accurately when folded together. To secure this action the shoulders 0, 0, 0, 0, Fig. 3, are formed and against which the angles of the plates hit, see'Fig. 4:, where the plates are shown in their places by dotted lines. These shoulders are so arranged as to permit each leg of. the rule to turn on 1ts center, or pivot, one

fourth of a revolution, or 90 degrees, and no more.

What I claim as my invention and desire to secure by Letters Patent is The peculiar form and construction of the double centered joint as above described, which render it capable of being applied'to rules. .These are, 1st, that the legs of the rule are made a necessary and constituent part of the joint, as the plates of brass with their pins or pivots, without the legs of the rule, could not form a joint. 2. The angular projections of the brass plates marked 1), b, in Fig. 1,'of the drawing. 3. The shoulders formed on the legs of the rule marked 0, c, 0, c, Fig. 3. The two last named particulars regulate the correct opening and folding of the rule, and insure the turning of each leg of the rule on its own proper center its equal share of the required half of a revolution.

, LEMU EL HEDGE.

Witnesses: NORMANA A. BURR, CLARENCE HEDGE. 

